<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {margin: 0; padding: 0}
        .nav {
            width: 400px;
            height: 400px;
            overflow: hidden;
            position: relative;
            margin: 100px auto;
            cursor: pointer;
        }
        .img1 {
            color: white;
            width: 400px;
            bottom: 0;
            font-size: 26px;
            text-align: center;
            line-height: 400px;
            background: rgba(0,0,0,.3);
        }
        .nav P {
            position: absolute;
        }
    </style>
    <script src="js/jquery-3.1.1.min.js"></script>
</head>
<body>
<div class="nav">
    <img src="image/1.jpg" width="400px" height="400px">
    <P class="img1" style="display: none">你看见了么！</P>
</div>
<script>
    $('.nav').hover(function () {
        $(this).find('p').fadeIn(1000);
    },function () {
        $(this).find('p').fadeOut(1000);
    });
</script>
</body>
</html>